I. Field of the Invention
The present invention is generally directed to a current controlling device and, more particularly, to a device that controls the flow of current by the position of a mobile charge within an insulating tunneling barrier.
II. Description of Related Technology
Currently, there is a great deal of interest in the development of single electron transistors, single molecule transistors, and in electronic devices created using nanotechnology to create electronic devices (such as memory circuits) with dimensions in the nanometer range. Nanoscale technology may increase the speed or circuit density of the next generation of integrated circuits.
A recent example of a nanotechnology electronic device is Hewlett-Packard's “Molecular Wire Crossbar Memory”, disclosed in U.S. Pat. No. 6,128,214. This memory device uses a two-dimensional array of a large number of nanometer-scale devices, each located at the junction of crossed nanometer-scale “wires”. The “devices” are bi-stable molecules such as rotaxane, pseudo-rotaxane, or catenane, and they are switchable between two states when voltage is applied to the pair of wires that create the junction. The state of one of these bi-stable molecules can be read non-destructively with a “read” voltage.
However, electrically active molecules often cannot withstand temperatures that are commonly reached during integrated circuit processing, hence the need for extremely fault-tolerant architectures. For example, one touted feature of Hewlett-Packard's Teramac custom computer that uses a nanowire grid connected by a monolayer of molecular switches was its ability to function correctly even though thousands of individual cells of its Field-Programmable Gate Arrays were defective to some extent.
Thus, a nanoscale current controlling device that uses standard thin-film and integrated circuit fabrication techniques could make possible improved integration into high-density memory arrays and other circuits.